Obesity and the GI Tract
Obesity and BMI
A person is considered obese when their body mass index (BMI) is 30 or higher. You can calculate your body mass index using our BMI calculator. For most, BMI provides a reasonably accurate body fat estimate. Athletes with high muscle mass may have a BMI in the obese category, even though excess body fat is not present.
- Below 18.5: Underweight
- 18.5-24.9: Normal
- 25.0-29.9: Overweight
- 30.0 and above: Obese
If you think you’re obese you should see a doctor who can review your health risks and discuss options for weight loss.
Overweight vs. Obese
People who have a BMI between 25 and 29.9 are considered overweight. A BMI of 30 or above is considered obese.
Nearly 40% of all adults in the United States (over 93 million people) are obese according to the CDC. The percentage is higher among Hispanics (47%) and non-Hispanic blacks (46.8%).
Causes of Obesity
Obesity is caused by taking in more calories than you burn. These extra calories are stored as fat. Obesity is occasionally linked to a medical condition, but these conditions (such as Prader-Willi and Cushing’s syndrome) are rare. Most often, obesity is caused by:
- An unhealthy diet – eating more calories than you burn will eventually lead to weight gain. Most American’s diets are too high in calories, and consuming high-calorie fast-food and drinks is common but unhealthy.
- Inactivity – People who aren’t active do not burn as many calories. Those who live a sedentary lifestyle are likely to take in more calories than they burn through normal activities and exercise.
Obesity Risk Factors
Obesity can be caused by many factors, and often a combination of:
- Genes: Your genetics may affect how much fat you store and where its stored in your body. Your genes may also play a role in how your body breaks down food and converts it into energy.
- Family Lifestyle: Obesity tends to run in families, but not only because of genetics. Family members typically share similar activity and eating habits.
- Inactivity: Your body burns fewer calories when you’re not active. A sedentary lifestyle makes it easier to overeat and gain weight. Some injuries or conditions (like arthritis) may make it difficult to exercise which can eventually lead to weight gain.
- Unhealthy Diet: High-calorie diets containing fast food, oversized portions, and high-calorie drinks often lead to obesity.
- Medical Conditions / Medicines: Some medicines can cause weight gain, and some medical conditions such as Prader-Willi and Cushing’s syndrome can lead to having excess fat.
Gastrointestinal Complications with Obesity
Obesity is a risk factor for many gastrointestinal conditions. For nonalcoholic fatty liver disease, obesity is a direct cause. Obesity can cause an increased risk of:
- gastroesophageal reflux disease
- Barrett’s esophagus
- esophageal adenocarcinoma
- erosive gastritis
- gastric cancer
- colonic diverticular disease
- colon polyps
- liver disease (e.g. nonalcoholic fatty liver disease)
- hepatocellular carcinoma
- acute pancreatitis
- pancreatic cancer
Prevention of Obesity
If you’re overweight or at risk of becoming obese, there are steps you can take to prevent unhealthy weight gain. These are the same steps as weight loss and include regular exercise, healthy eating, and a long-term commitment to these behaviors.
- Regular exercise – Around 30 minutes of moderate exercise each day. This can be as simple as walking quickly.
- Eat a healthy diet – Eat more low-calorie foods like fruits, vegetables, and whole grains. Avoid high-calorie choices like fried foods. You should also limit the amount of sugar and alcohol you consume.
- Monitor your weight – People who weigh themselves once a week are more likely to maintain a healthy weight. You can measure your progress each week to see if your efforts are working.
- Stick with it – A lifestyle that includes activity and healthy eating needs to be a long-term commitment. It’s important to find a plan that you can maintain. Visiting with a registered dietitian can help.